In recent years, thin flat panel displays (FPD) as a display device are becoming popular, instead of CRT (cathode ray tube) display devices which have conventionally been mainly used. In the FPDs, display elements such as liquid crystal, light-emitting diode (LED), and organic electroluminescence (organic EL) are utilized. Among such FPDs, display devices utilizing liquid crystal have been studied and developed actively, because of their advantages such as thin body, light weight, and low power consumption.
FIG. 6 schematically illustrates a configuration of a pixel of such a liquid crystal display device. In general, in a pixel 41, (i) a gate bus line 7 and a source bus line 8 are arranged so as to perpendicularly intersect with each other, and (ii) a common line 9, which is a wire for forming a storage capacitor (Cs), is arranged in parallel with the gate bus line 7. Meanwhile, a common electrode 4 and a pixel electrode 6 are provided so as to overlap each other, and a thin film transistor (TFT) is provided at an intersection of the gate bus line 7 and the source bus line 8 as a switching element (active element). Here, in a case where wiring of the common electrode 4 is made of a material having relatively high resistance, a defective display such as a cross talk may be caused.
In order to prevent such a defective display, a technique has been developed in which a contact hole is provided for connecting the common electrode with the common line so that wiring resistance of the common electrode is reduced. For example, Patent Literature 1 discloses a configuration in which each of contact holes, which connect a common electrode with a common line, is provided for each set of a plurality of pixels, and the contact holes are arranged in a staggered manner.
According to the configuration, the common electrode having high resistance is connected with the common line having low resistance so as to (i) reduce wiring resistance and (ii) decrease a probability of short circuit between a bus line and the common electrode via the contact hole.